they then sped off in a white kia van, with what the fbi now says is a significant amount of cash. the bomb looked convincing enough, but when the bomb squad finally detonated it -- it turned out to be fake. you can see the front entrance of this branch has all the security measures you'd expect, but the robbers used a side entrance here where there are no cameras. they appear to have known enough about the bank's security to avoid getting their pictures taken. the bank robbers clearly did their homework. so how often do you catch these guys? >> 60% of the time we're able to identify the victims and catch them. >> reporter: so 40% of the time, the bank robbers get away? >> well, 60% of the time they do get caught. >> reporter: with no surveillance pictures to go by, the fbi's strongest lead may be the branch manager. that's her being walked out to safety. she's now in protective custody. and the manhunt is on for those two masked men. david wright, abc news, los angeles. >>> coming up right here, isaac strikes again. the storm in the gulf, coming back for more. 8% every 10 years. w